This invention relates to acoustic control devices and, more particularly, to acoustic switches for remotely controlling the functions of an auxiliary device coupled thereto.
There are many remote control devices which have been devised to respond to signals transmitted from remote locations for control of auxiliary devices. These devices can be arranged to respond to signals in various frequency ranges and in the past have been relatively complex. An improvement in these devices is disclosed in my copending application Ser. No. 474,875, filed on May 31, 1974, now U.S. Pat. No. 3,970, 987. This improved device is arranged to be responsive to acoustic signals in the sonic and ultrasonic frequency range and, in response to these signals, to control a function of an auxiliary electrical device. A specific application of this device for remotely controlling the channel selection function of a television receiver is disclosed in my copending application Ser. No. 567,410, filed on June 11, 1975, now U.S. Pat. No. 3,988,680.
Though the devices disclosed in the above-referenced applications work quite satisfactorily, there are possibilities for improving their operation. For example, the remote control devices described above can readily control only one function of the auxiliary device to which they are coupled. Thus, the devices may be adapted for controlling the electrical power to the television receiver, or the channel selection function of the television receiver, but not both functions. In the television remote control unit disclosed in Ser. No. 567,410, for example, the channel selection function is controlled by the acoustic switch, but the electrical power to the receiver is controlled by a mechanical switch arranged to operate at only one position of a tuner.
In my copending application Ser. No. 476,439, filed on June 5, 1974, now U.S. Pat. No. 3,892,920, an acoustic remote control device is disclosed which can readily control more than one function of an auxiliary device coupled thereto. This device employs two separate tuned transducers which are alternately activated to respond to acoustic signals in a predetermined frequency range.
When a first of the transducers is activated, a bistable device coupled thereto is switched between a first and second stable state in response to an acoustic signal detected by the first transducer to control one function of the auxiliary device. When a second of the transducers is activated, a monostable device coupled thereto is switched between a stable and an unstable state in response to an acoustic signal detected by the second transducer to control another function of the auxiliary device. When used, for example, to control a television receiver, the device can thus control both the channel selection function of the receiver and the flow of electrical power to the receiver independently of the position of the tuner in the receiver. It would be desirable to have a device which possesses the multiple function control capabilities of the acoustic remote control device disclosed is Ser. No. 476,439, and which is also simpler in construction and less expensive to produce.